Here's the thing. Statham is a decent-enough action actor. But I haven't yet seen him stretch dramatically. While this show is definitely an action-based show, the cast is mostly made up of dramatic actors, rather than action stars.
My concern would be that a guy like Statham would "action" it up, rather than trying to find the dramatic truth of the role. True, Bullseye is an action-oriented character. He's an insane, obsessed killer with perfect aim and amazing combat abilities. But I think it'd be more important to get his character right in terms of what drives him, what motivates him, and why he becomes obsessed with Daredevil, with being the best, etc. Especially if they bring in Elektra and play out the triangle there and the rivalry between Bullseye and Elektra for the top assassin position for the Kingpin.
None of this is to say that Statham can't play the role. He might be perfectly able to. I just haven't seen him in anything that would require the kind of performance I'd expect from this version of Daredevil, which is far more rooted in drama than in action (which is, in my opinion, what makes it work so well).
To be clear: if this were a straight up "Put what's on the page on the screen," I'd say Statham would be fine. Bullseye on the page -- in Frank Miller's run, anyway -- is someone he could easily play. But those comics are almost 40 years old at this point, and they are not what's being depicted in the show. If they were performed by actors, the acting would be far more "broad" now. In their day, they were plenty gritty, but 40 years later, they're a bit less grounded. Certainly they aren't as grounded as the show. Now, the Born Again arc....that's a whole other story, but we'll see if that makes it to the screen.